Internal combustion engine



Aug? 26, 1941- G. R. ERiCSON x 2,254,173

INTERNAL COMBUSTION ENGINE Filed Dec. 5, i940 GEORGE R. ERICSON I ATTORNEY.

Patented Aug. 26,1941 I 2 UNITED STATES PATENT OFFICE 2,254,173 INTERNAL COMBUSTION ENGINE George R. Ericson, Kirkwood, Mo.- Application December 5, ,1940,Serlal No. 368,642 Claims.- (01. 123-48) This invention relates to internal combustion engines of the four'stroke type and moreparticw larly concerns combustion chambers and intake valves.

In the design of internal combustion engines the extent to which the combustible mixture can be compressed without resulting in pre-ignition or objectionable detonation must be considered. The practical, degree to which the charge can be compressed will depend, among other thin s. upon the characteristics of the fuel to be used and the design and degree of cooling of the combustionchambers. It is desirable, however, from the standpoint of efliciency to compress the combustible mixture to the practical maximum permlssible with any particular set of condition. In the throttle controlled type engine it will be seen that during throttled operation, the reduced amount of combustible mixture which can be drawn into the cylinders will not be compressed to as great an extent as the full charge which can be drawn in during wide open throttle operation. It will appear to be advantageous therefor, from the standpoint of efliciency, to increase the compression ratio as the indrawn charge is reduced, either by throttling or at high speed operation by restriction, in order to appi'oach to some degree the maximum practical, compression. The practical way tovary the compression ratio is of course to vary the'combustion space.

There is the further consideration of valve timing in engine design; and as a fixed valve timing. is, for the purpose of economizing, usually employed to take care of a wide range of oper ating speeds it will be seen that some loss in,

well known and their details having no bearing on I the present invention. Acylinder head II is provided having'a recess l2 therein which forms a part of the full combustion chamber. Leading from the inlet port l3'in the left side of the block to the recess i2 is a curved passage H which together with recess I2 forms the full combustion chamber. Attached to the side of the block and registering with port I3 is an intake conduit I5 volume at the lower speeds will result if the valves are timed to open and close sufficiently 7 early in the cycle to take care of the higher intake velocities occurring at higher speeds.

It is an object of the present invention to pro- .vide an internal combustion engine of the four stroke typ having a throttle controlled intake conduit and in which means responsive to a decrease in pressure in the intake conduit for increasing the compression ratio is provided.

It is a further object of the present invention to provide novel intake control mechanism for an engine of the above character which results in greater volumetric efliciency over a range of engine speeds.

Other objects and advantages will appear in the following description andaccompanying drawing referring to which:

Fig. 1 is a transverse section through the upper on which is mounted the carburetor 9. A valve seat 16'' is formed at the junction of passage I4 and recess l2 and is adapted-to seat an intake valve Hi. The intake valve I6 is engine actuated in a conventional manner under certain conditions of operation. That is, the cam shaft 1 is geared to the crank shaft and moves the valve l6 upward. there being a cam the valve stem and the cam, strong valve spring l8 urges valve seat I9 is formed in the conduit I 5 near its connection to the block, this seatbeing adapted to seat a second intake valve 20." The stem 2| of valve 20 is guided in a boss 22 and carries atand a comparatively tached to its outer end a piston 23. The piston 23 reciprocates ina cylinder 24 formed as a part of the conduit casting I 5. and is exposed to atmospheric pressure on the left side and the intake conduit pressure'on the right side. A spring 25 casting. The outerend of cylinder 29 is closed by a plug 30 and the cylinder is at this end in portion of a vertical engine incorporating one communication with the intake means of a passage 3|. The inner or right end of cylinder 21 is vented to atmosphere at 32. Thus, it will be seen that piston 21 operates between conduit by atmosphere and the pressureexlsting in the intake conduit. A spring 23 bearing on 'cylinder 29 and block '26 normally urges block 26' and piston 21 toward theright. .The upper end of cam follower I1 is provided with a collar 34 which follower between it closed. A second as indicated in Fig. 2.

abuts block 26 under certain operation conditions to hold valve IS in an open or inoperative position as indicated in Fig. 2. A throttle valve 35 is indicated in the lower part of carburetor 9 and functions in a well known manner to control the speed of the engine.

In operation with the throttle wide open and the engine operating at comparatively low speed due to a heavy load, the velocity through the intake conduit will be comparatively low and the pressure therein consequently comparatively high. Under these conditions the spring 33 will be permitted to move block 26 into a blocking position under collar 34 of the cam follower l1 Thus rendering valve 26 inoperative. Under these same conditions, spring 25 will be permitted to lightly seat valve 20 and the engine will then be operating with the full combustion space. The valve 20 under these conditions will open and close automatically on the intake and compression strokes and of course is held closed by pressure during the working and discharge stroke. The spring 25 must obviously be comparatively light in order to minimize volume loss in the work necessary to open this valve on the intake stroke. As the speed of the engine is increased under wide open throttle conditions the velocity through the intake conduit will increase and as a consequence the pressure therein will drop and at a predetermined point the piston 23 will move to the right holding valve 20 open and piston 21 will move to the left removing block 26 from its blocking position and thereafter the engine will operate with the reduced combustion space pos terior to valve l6 and valve l6 will operate to control the intake. During operation under any appreciable degree of throttling the pressure in the intake conduit will be sufliciently low to render valve 20 inoperative and hold out block 26.

It is apparent from the foregoing, therefore, that under conditions of operation wherein the intake charge is reduced a predetermined amount by throttling or by intake conduit restriction at the higher speeds the combustion space will be automatically reduced resulting in an increased compression ratio. The foregoing description and accompanying drawing are intended to be illustrative and not limiting and the exclusive use of all modifications within the scope of the appended claims'is contemplated. I

I claim:

1. In an internal combustion engine, a combustion chamber, an inlet to said chamber, an intake conduit leading to said inlet, a pair of intake valves arranged in series either of said valves being capable of controlling said inlet, one of said valves being engine operated and the other of said valves being flow responsive, and means for rendering said engine operated assent valve inoperative under conditions oi comparatively high pressure in said intake conduit.

2. In an internal combustion engine, a combustion chamber, an inlet to said chamber, an intake conduit leading to said inlet, a pair of intake valves arranged in series, either of said valves being capable of controlling said inlet, one of said valves being engine operated and the other of said valves being flow responsive, said engine operated valve being posterior to said flow responsive valve, and means for rendering said engine operating valve inoperative under conditions of comparatively high pressure in said intake conduit.

3. In an internal combustion engine, a cylinder block, a head for said block, a cavity in said head, an intake passageway in said block leading to said cavity, said cavity and said intake passageway comprising a combustion chamber, an engine operated intake valve dividing said cavity and said passageway when closed, a second intake valve controlling said passageway anterior to said first mentioned valve, an intake conduit leading to said passageway, blocking means for rendering said first-mentioned valve inoperative, means responsive to a predetermined vacuum in said intake conduit for rendering said blocking means inefiective, and means responsive to a predetermined vacuum in'said conduit for rendering said second valve inoperative.

4. In an internal combustion engine, a cylinder block, a head for said block, an inlet port in saidblock, a combustion chamber, a portion of said combustion chamber comprising a cavity in said head, another portion of said chamber having the form of a. passageway leading from said inlet port to said cavity, a valve at the outlet of said passageway dividing said passageway and said cavity when closed, said valve being opened by engine driven means and closed by spring means, spring pressed blocking means for holding said valve open under certain conditions, a

v second valve for controlling said passageway near said inlet port, said second valve being flow responsive, an intake conduit leading to said inlet intake in fixed relation to definite points in the engine cycle during throttled operation, and

opening and closing the intake in response to pressure reversals, caused by the reciprocation of the engine piston, during unthrottled operation.

GEORGE R. ERICSON. 

